Carburizing apparatus



P 12, 1933- A. w. MACHLET 1,938,599

CARBURI Z ING APPARATUS Filed March 21, 1930 INVENTOR fldolph ZUMcw/zlat A! ;ORNEY Patented Dec. 12, 1933 UNITED STATES PATENT OFFICE CARBURIZING APPARATUS f Adolph W. Machlet, Elizabeth, N. J.

Application March 21, 1930. Serial No. 437,790

3 Claims.

This invention pertains to the same general subject matter as my Patent No. 1,745,104, granted January 28, 1930, for an Improved carburizing process. The present invention, however, relates to improved apparatus in which such a process and analogous processes for carburizing with rich hydrocarbon gases may be practiced.

In my United States Patent No. 1,337,244 a carburizing apparatus which is designed to operate with hydrocarbon gases generally, is described, but rich hydrocarbon gases are not specially adapted to be used in the apparatus of said patent, because of their tendency to deposit uncombined carbon on the work. Carburizing apparatus of the general type shown in said patent may however be combined with additional apparatus designed to prevent the deposit of carbon from such rich gases, and will be hereinafter described in detail.

One object of the present invention is to provide an improved carburizing apparatus in which the richer hydrocarbon gases may be utilized to advantage for the carburizing of articles of ferrous metal, in an improved and economical manner, and other objects will appear from the detailed description of the preferred construction and be pointed out in the claims.

I find most efficient and economical results to be produced by designing my apparatus so as to first mix a rich gas such as, for instance, propane with air, then to ignite the mixture in a confined space, usually the closed, externally heated retort, thus changing the mixture into an intermediate gas containing at least some carbon monoxide. This intermediate gas is caused to flow upon and gradually penetrate the ferrous metal articles in the closed retort and carburize same exceedingly well and at a very economical cost.

Propane is a rich hydrocarbon gas, at normal atmospheric pressure and temperature, which is usually compressed and liquefied to facilitate transportation. It is usually shipped in flasks under a pressure of 110 pounds, more or less, per square inch. I have found propane a convenient and economical gas for use in my improved carburizing apparatus. However, any rich gas free from sulphur and other deleterious substances may be used successfully in my improved apparatus. A typical apparatus, particularly designed to use propane, will be described in the detailed description of the preferred construction.

Referring to the accompanying drawing:

The numeral indicates a flask containing liquid propane. Flask 10 is provided with a control valve 14 from which the liquid propane flows (Cl. 266-5) A at a reduced pressure indicated by gauge 13, thence through the pipe 12 into a bell, gasometer, or gas and air mixer, 11, wherein the liquid propane expands to gaseous form. Mixer 11 is also provided with an air inlet 14a, and the mixture in mixer 11 should contain about three or four parts of air to one part of propane gas. It may be noted that a ten to one mixture of air and gas is explosive but that the richer mixtures, such as I prefer to use, are comparatively non-explosive. Mixers such as the mixer 11 are usually provided with conventional, adjustable means i (not shown) for regulating the proportions of the volumes of the gases forming the different mixtures.

One well known apparatus for mixing the air and gas in any desired proportions is the Schematische Darstellung eines Selas-Apparates. In such apparatus air is drawn into the mixer through an inlet, for instance, inlet 14a. A pump 15, driven by a belt pulley 16, draws the mixture from the mixer 11, and may be provided with the automatic by-pass device 17. Such a by-pass 17 is well known and is frequently used in air or gas pumps, to permit the mixture to flow idly back from the discharge end 18 to the intake end 19 of the pump when the pump is pumping the mixed gas and air faster than is required or when the discharge of the pump is completely closed by, for instance, the valve 22 hereafter further described.

From the pump 15 a flexible hose 20 conducts the mixture to a pipe 21 in which there is provided a valve 22 to control the supply of the diluted gas to the revolving carburizing retort 23, which encloses the articles to be carburized, and the retort 23 is externally heated in a furnace 24. Immediately upon entering the retort the mixture is ignited by the heat of the retort and converted into an intermediate gas which gradually penetrates the ferrous articles and carburizes same. The retort and furnace may be constructed in the same general manner as is disclosed in said Patent No. 1,337,244, to which reference has heretofore been made. In the drawing of the present invention the revolving retort bears the numeral 23, the furnace 24, the retort cover 25, the vent for spent carburizing gas 26, and the heating burners 34.

Variations may be resorted to within the scope of the invention, portions of the improvements may be used without others, and the measure of the invention is defined by the appended claims.

I claim:-

l. A carburizing apparatus including a tank closed retort and a connection thereinto from the mixing means.

3. In a carburizing apparatus, means for supplying gas, a power driven mixing means provided with a free air intake connected thereto, a closed retort provided with a heated entrance portion and a heated body portlon and a connection into the entrance portion from the mixmg means.

ADOLPH W. MACIHIET. 

